Screen bar corner reinforcement, a screen frame including such a reinforcement and methods of manufacturing these products

ABSTRACT

A corner reinforcement for use in strengthening screen frames, for example, includes at least a first segment and a second segment of screen bar, each formed into a desired profile and each having a hollow interior portion, a reinforcing channel and a rigid reinforcing and structural material. The reinforcing channel has a first leg and a second leg arranged at approximately ninety degrees to the first leg with ends of the channel securing first and second extensions to extend the first and second legs, respectively. At least a portion of (i) the first extension of the channel is inserted through a first end of the first segment of the screen bar into and substantially spaced from surfaces of the hollow interior portion thereof and (ii) the second extension is inserted through a first end of the second segment of the screen bar into and substantially spaced from surfaces of the hollow portion thereof. The rigid reinforcing and structural material, formed from a foamed chemical, is inside at least one of (i) the hollow interior portion of the first segment for securing the inserted portion of the first extension of the reinforcing channel therewithin and (ii) the hollow interior portion of the second segment for securing the inserted portion of the second extension of the reinforcing channel therewithin. Also disclosed is a screen frame including such corner reinforcements, as well as methods for making these products.

RELATED APPLICATION INFORMATION

This application is a continuation-in-part of application Ser. No.08/729,275, filed Oct. 10, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a reinforcement for architectural orstructural members such as frame sections or frames for screens,windows, doors, plastic or transparent panels, and the like, and moreparticularly, a screen bar corner reinforcement for use instrengthening, for example, screen door or window screen frames made ofaluminum or sheet steel, a screen frame including such a reinforcementand methods of manufacturing these products.

2. Description of the Related Art

For convenience of discussion, the invention will be defined anddescribed with particular reference to screen bar reinforcement for usein screen frames. Nevertheless, it will be understood that the inventionis of general utility. Metal frames for window screens, screen doors(such as patio door screens) and the like are commonly made of fourelongated frame members of uniform cross section connected together bycorner assemblies. These frames are typically roll-formed from aluminumor sheet steel, although some may be extruded aluminum, and some ofthese frames are foam-filled to increase their strength. (For example,U.S. Pat. No. 3,885,371 shows a roll-formed sheet metal window framefilled with a rigid lightweight foamed material such as polyurethane.)Conventionally, to secure the screen material to the above-noted frames,peripheral edges of the screen are held within open grooves formed alonginside edges of the frames using a stuffer strip known as spline.

These frames must have adequate strength as well as longitudinal andtorsional rigidity, and the corners and joints must be rigid. Theseframes also must be durable and resist impact, damage and corrosion.Further, these frames must meet at least these practical requirementswithout excessive weight or cost.

In the case of large screen frames, particularly those used for patiodoor screens, prior corner connectors have been inadequate tosufficiently prevent twisting or bending of the frame. The twisting orbending of the frame out of its plane is particularly troublesome whenthe frame is removed from its support framing, for maintenance orcleaning, and then an attempt is made to replace it. The twisting orbending also presents problems during normal operation if the framebinds in its support tracks.

U.S. Pat. No. 4,570,406 shows an inexpensive, molded plastic cornerconnector key, which frictionally interconnects with the end portions ofconventional screen frame members that can be square cut rather thanmitered. The corner connector itself forms the exposed corner of theframe and thus is sized and shaped to match or blend with the ends ofthe frame members to form a visually uniform frame. The connector keyhas two rectangular, tubular-shaped legs arranged at right angles. Thelegs integrally fit within and are frictionally locked in face-to-facecontact against the interior wall surfaces of the frame members.

U.S. Pat. No. 5,431,211, commonly assigned to the assignee of thesubject application, shows a corner assembly for a window screen frame.The corner assembly has a pair of connector arms extending outwardlyfrom a corner connector, generally at ninety degrees relative to eachother. The connector arms are telescopically received in grippingrelation within corresponding channels of side members of the frame.

U.S. Pat. No. 4,651,482 shows a corner piece for connecting adjacenthollow spacer members to form a spacer frame used in the construction ofthermally insulated windows. The corner piece includes horizontal andvertical legs formed at a right angle. One end of each leg has a cuttingedge. When the ends of each leg are inserted into a hollow spacer, whichhas internal partitions, the sharpened cutting edge is able to cutaround the adjacent partition to enter the spacer. Sealant may beinjected into the corner pieces and the spacers after assembly to sealoff any gaps around the installed corner piece.

The foregoing corner connectors have a significant drawback, however, inthat wedging the corner piece into the frame member can deform the framemember. This may result in jamming of the frame member during movementin its track or guide. Also, these current corner connectors concentrateloading of force at the points of contact, rather than distributing theloading. Such point loading results in local, permanent deformation ofthe light gauge metal frame members near the point loads. Once permanentdeformation occurs, a clearance gap is formed, which allows movement(i.e., play) between the corner insert and the frame member. This playlessens the stiffness of the corner connection and the integrity of theentire frame assembly. Once clearance is established, and movementallowed, the connection is "worked" in operation and clearances increasefurther. To reduce the local deformation, thicker gauge frame membersare required. This increases costs.

The initial clearances that are required between the corner insert andthe frame members in order to insert current corners connectors also canreduce corner rigidity and torsional strength. A certain clearance isnecessary to allow easy, hand assembly of the corner insert in the frameassembly. Although a snug fit is desired, practical stamping/molding androll-forming tolerances allow play, which should be avoided, asdiscussed above. To reduce this play, and to prevent the cornerconnector from sliding out, some have proposed bending portions of thealuminum roll-formed section of the frame into pre-cut holes in themetal corner connector. This is known as staking.

Patio screen doors, in order to slide in their tracks, are usuallyprovided with wheels mounted at the four corners of the door frame. Forexample, U.S. Pat. No. 3,729,868 shows a screen door having L-shapedcorner connectors that include extensions which frictionally fit intointerior spaces of the door frame. A sidewall of each connector isaligned with a rail of the door frame and includes a cutout that enablesa guide roller or wheel to protrude therethrough. The roller is mountedto a bracket in a hollow interior space of the connector and pivotsabout a pin anchored in the connector. A leaf spring biases the rollerinto the rail of the door frame. The device in the '868 patent, whilesimplifying construction of the screen door, does not provide a framehaving adequate strength and longitudinal and torsional rigidity,especially at the corners.

Accordingly, a need has arisen for a screen bar corner reinforcement anda screen frame including such a reinforcement, which overcome thedrawbacks noted above with respect to conventional corner assemblies.There is an additional need for methods of making these products.

SUMMARY OF THE INVENTION

An object of this invention is to address the foregoing needs in the artand to provide a screen bar corner reinforcement for use instrengthening screen door or window screen frames, for example.

In one aspect, the screen bar corner reinforcement of this inventionincludes at least a first segment and a second segment of screen bar,each formed into a desired profile and each having a hollow interiorportion, a reinforcing channel, and a rigid reinforcing and structuralmaterial. The reinforcing channel has a first leg and a second legarranged preferably at approximately ninety degrees to the first leg. Atleast one of (i) a portion of the first leg of the reinforcing channelis inserted through a first end of the first segment of the screen barinto and substantially spaced from a surface of the hollow interiorportion of the first segment and (ii) a portion of the second leg of thereinforcing channel is inserted through a first end of the secondsegment of the screen bar into and substantially spaced from a surfaceof the hollow portion of the second segment. The rigid reinforcing andstructural material, formed from a foamed chemical, is inside at leastone of (i) the hollow interior portion of the first segment for securingthe inserted portion of the first leg of the reinforcing channeltherewithin and (ii) the hollow interior portion of the inserted portionof the second segment for securing the inserted portion of the secondleg of the reinforcing channel therewithin.

In another aspect, the present invention provides a method of makingsuch a screen bar corner reinforcement for use in strengthening screenframes.

Another object of the present invention is to provide a screen frameincluding screen bar corner reinforcements. The frame includes first andsecond short segments of screen bar and first and second long segmentsof screen bar, each segment being formed into a desired profile and eachhaving a hollow interior portion, four reinforcing channels, and a rigidreinforcing and structural material. Each of the reinforcing channelshas a first leg and a second leg arranged at approximately ninetydegrees to the first leg. At least one of (i) a portion of the first legof a respective reinforcing channel is inserted through an end of eachshort segment of the screen bar into and substantially spaced from asurface of the hollow interior portion of the short segment and (ii) thesecond leg of a respective reinforcing channel is inserted through anend of each long segment of the screen bar into and substantially spacedfrom a surface of the hollow interior portion of the long segment. Therigid reinforcing and structural material, formed from a foamedchemical, is inside at least one of (i) the hollow interior portion ofeach short segment for securing respective inserted portions of thefirst legs of the reinforcing channels therewithin and (ii) the hollowinterior portion of each long segment for securing respective insertedportions of the second legs of the reinforcing channels therewithin.

The present invention, in yet another aspect, provides a method ofmaking a screen frame including such screen bar corner reinforcements.

In the present invention, each of the segments of the screen bar have arecess for securing screen, for example, therein and are made of amaterial selected from the group consisting of extruded aluminum,roll-formed aluminum, roll-formed sheet steel, extruded plastic andpultruded, glass-reinforced thermosetting resin.

In the present invention, the inserted portions of the reinforcingchannel are sufficiently spaced from the surfaces of the hollow interiorportions of the screen bar segments for allowing the foamed chemical,prior to curing, to pass between the inserted portions and the surfacesof the hollow interior portions.

The reinforcing channel, and particularly the legs of the reinforcingchannel, can be made of more than one piece, or of several pieces,joined together. In one aspect, the reinforcing channel can have asubstantially U-shaped cross section and a bend at approximately ninetydegrees, with the ends of the channel being crimped, roll-formed,knurled, welded or otherwise modified to secure extensions, such asreinforcing bar (preferably steel reinforcing bar) extensions, toconstitute the first and second legs of the reinforcing channel. Ofcourse, the extensions can be made of other suitable materials. Also,the reinforcing channel can be a unitary piece preferably having eithera substantially U-shaped cross section or a substantially Z-shaped crosssection and has a bend at approximately ninety degrees to form the firstand second legs.

The reinforcing channel can be steel, preferably plated, or made of ahigh strength resin or plastic. The cross section of the reinforcingchannel is significantly smaller than cross sections of the hollowinterior portions of the screen bar segments for allowing the foamedchemical to pass between the reinforcing channel and a surface of thehollow interior portions.

In another aspect, a wheel mechanism can be secured to one of the legsof the reinforcing channel, the wheel mechanism including a wheel forbeing guided in a track of the screen frame. In one aspect, the centerline of the wheel mechanism is aligned with the center line of the legof the reinforcing channel to which the wheel mechanism is secured. Adecorative cover, including side panels, can encase the wheel mechanism.

In the present invention, the screen bar segments can include injectionapertures, with the structural material being, for example, polyurethanefoaming material, having been injected into the segments through theinjection apertures and solidified. If desired, each screen bar segmentcan include a retainer to limit or define the foamed region of thescreen bar segment. In this aspect, the foamed chemical is injecteddirectly into the screen bar segment and is substantially retainedtherein by the retainer. If an extension is utilized with the retainer,the portion of the extension opposite the foamed side of the retainercan be, if necessary, painted or otherwise treated chemically, forexample, to protect against weathering, rust, corrosion and the like.

In another aspect, the decorative cover can be enclosed and be providedwith an injection aperture for the injection of the foaming material.Thus, the rigid reinforcing and structural material, formed from afoamed chemical, also can be provided from inside regions of thedecorative cover.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically shows a portion of one embodiment of thereinforcing channel used in the screen bar corner reinforcement of thepresent invention, including an optional wheel assembly.

FIG. 1B schematically shows a portion of another embodiment of thereinforcing channel used in the screen bar corner reinforcement of thepresent invention, including an optional wheel assembly.

FIG. 1C schematically shows a portion of the roll-formed screen bar usedin the present invention, prior to being injected with a rigidreinforcing and structural material, formed from a foamed chemical, andprior to insertion of the reinforcing channel shown in FIG. 1A or FIG.1B.

FIG. 2A shows, as one embodiment of the present invention, thereinforcing channel and optional wheel assembly of FIG. 1A with aportion of the decorative cover for covering the wheel assembly.

FIG. 2B shows the reinforcing channel of FIG. 2A with the decorativecover, and connector caps that can be provided, in place.

FIG. 2C is a partial cutaway, perspective view showing, as an alternateembodiment of this invention, the reinforcing channel and optional wheelassembly with a portion of the decorative cover for covering the wheelassembly.

FIG. 3 shows a partially assembled view of one embodiment of the cornerreinforcement of the present invention.

FIG. 4 shows a cross-sectional view of one embodiment of the cornerreinforcement of the present invention, taken generally along lineIV--IV of FIG. 5.

FIG. 5 shows an assembled view of a screen frame including the screenbar corner reinforcements of the present invention.

Like reference numerals have been used for like or correspondingelements throughout the views.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1A schematically shows a portion of one embodiment of a reinforcingchannel 100A used in the screen bar corner reinforcement of the presentinvention (which will be discussed in more detail below), including anoptional wheel assembly 200. In this embodiment, the reinforcing channel100A is preferably a unitary piece having a substantially U-shaped crosssection and a bend preferably at approximately 90° to form a first leg110A and a second leg 120A. The reinforcing channel 100A can be made ofeither steel, preferably plated, or a high strength resin or plastic,for example. If desired, other materials can be used, provided theyresult in the desired strength and rigidity achieved by the presentinvention. If made of plated steel, the reinforcing channel 100A can beroll-formed from flat stock. If made of high strength plastic, thereinforcing channel 100A can be molded or extruded. Representativedimensions for leg 110A, for example, of the reinforcing channel 100Aare 0.500 inches in overall height for arms 111A and 113A, 0.400 inchesin overall width for base 112A and 0.078 inches in thickness. However,these dimensions can be varied as desired.

Wheel assembly 200 includes a wheel 210 mounted to wheel assembly frame205 by axle 220. The wheel assembly 200 may be of the type discussed inmore detail in published Canadian patent application No. 2,111,918.Wheel assembly frame 205 includes a wheel well 206 formed by flaredportion 207. Flared portion 207 flares outwardly from wheel assemblyframe 205 by a sufficient amount to form wheel well 206. A set screw 230adjusts the height of the wheel assembly 200 when wheel assembly 200 issecured in place using a fastener or pin 240 (best seen in FIG. 2A).Fastener 240 is inserted through a hole 112A drilled or otherwise formedin first leg 110A of reinforcing channel 10A. A center line of the wheelassembly 200 is aligned with a center line of first leg 110A ofreinforcing channel 100A, to which it is attached.

FIG. 1B schematically shows a portion of another embodiment of areinforcing channel 100B used in the foam-filled screen bar cornerreinforcement of the present invention (which will be discussed in moredetail below), including a portion of optional wheel assembly 200. Inthis embodiment, the reinforcing channel 100B is preferably a unitarypiece having a substantially "Z-shaped" cross section and a bendpreferably at approximately 90° to form a first leg 110B and a secondleg 120B. Although I use the term "Z-shaped", in this embodiment,reinforcing channel 100B has three substantially straight segments 121B,122B and 123B each arranged at approximately 90° sequentially from theother. The reinforcing channel 100B can be made of either steel,preferably plated, or a high strength resin or plastic, for example. Ifdesired, other materials can be used, provided they result in thedesired strength and rigidity achieved by the present invention. If madeof plated steel, the reinforcing channel 100B can be roll-formed orstamped from flat stock. If made of high strength plastic, reinforcingchannel 100B can be molded or extruded.

The 90° bends of the reinforcing channel 100A or 100B will accommodatesquare or rectangular frames, for example. Nevertheless, other anglescan be used for other geometries. In fact, if desired, the reinforcementof this invention could be circular, oval, elliptical or otherwise.Also, as will be discussed in more detail below, the legs of thereinforcing channels could be separate pieces if desired.

I am using the term "reinforcing channel" to refer to members having asubstantially U-shaped cross section, as shown in FIG. 1A or asubstantially Z-shaped cross section, as shown in FIG. 1B, as well as toinclude other geometries, taken individually or in combination, such asround, square, rectangular, and the like, whether completely enclosed orpartially enclosed.

Representative dimensions for second leg 120B, for example, ofreinforcing channel 100B are 0.375 inches in height for segment 121B,0.750 inches in width for segment 122B and 0.375 inches in height forsegment 123B. Second leg 120B is typically 0.750 inches in overallwidth, 0.500 inches in overall height and 0.100 inches in thickness.However, these dimensions can be varied as desired. Further, thesedimensions will depend on the dimensions of the fillets and roundsgenerated when the reinforcing channel 100B is formed.

Wheel assembly 200 shown in FIG. 1B includes those features discussedabove with respect to FIG. 1A. FIG. 1B further shows holes 208 formed inwheel well 206 of wheel assembly frame 205 for receiving axle 220 (notshown). Although not shown in FIG. 1B, set screw 230 is provided foradjusting the height of the wheel assembly 200 when wheel assembly 200is secured in place using a fastener or pin 240.

Since, in this embodiment, wheel assembly 200 includes wheel well 206formed by flared portion 207, segment 121B of reinforcing channel 100Bmust be stamped or machined as shown by region 124B in FIG. 1B. Region124B is recessed sufficiently to accommodate wheel well 206 of wheelassembly 200. Of course, one having ordinary skill in the art recognizesthat if wheel assembly 200 does not include flared portion 207, then itis not necessary to provide recessed portion 124B in reinforcing channel100B. An advantage provided by this embodiment is that wheel assembly200 is constrained on only one side, by segment 121B, rather than beingconstrained by the two sides of reinforcing channel 100A shown in FIG.1A. This assists in locating and mounting wheel assembly 200.

FIG. 1C schematically shows a portion of the roll-formed screen bar 300used in the present invention, prior to being injected with a rigidreinforcing and structural material, formed from a foamed chemical, andprior to insertion of the legs of the reinforcing channel of thisinvention. As discussed above, for ease of discussion, the inventionwill be defined and described with particular reference to screen barfor use in screen frames. Nevertheless, it will be understood that theinvention is of general utility such as for frame sections or frames forwindows, doors, plastic or transparent panels and like architectural orstructural members. The screen bar 300 has a hollow interior portion 310and a groove 320 for receiving, for example, screen (not shown) therein.Conventionally, the screen is secured in groove 320 using a stufferstrip known as spline. Of course, other equivalent techniques may beused, if desired. The screen bar 300 also includes bent portions 330,which are bent 180°, in order to form a guide trough 340 for slidingalong a track of a screen frame, which will be discussed in more detailbelow. Screen bar 300 is typically rolled-formed from aluminum or sheetsteel, although it also may be extruded from aluminum. Further, it maybe extruded plastic or pultruded, glass-reinforced thermosetting resin,for example. Also, I have found that guide trough 340 is a preferredlocation for injecting the foamed material, as will be discussed in moredetail below.

FIG. 2A shows, as one embodiment of the present invention, thereinforcing channel 100A and optional wheel assembly 200 of FIG. 1Aassembled to a decorative side panel 250, which, together with a matingdecorative side panel 260 shown in FIG. 2B, forms a decorative cover 270for covering the wheel assembly 200. Side panel 250 includes pins 251Athrough 251C and receptacles 252A and 252B for securing matingdecorative side panel 260 shown in FIG. 2B. Side panel 260 includescorresponding pins and receptacles (not shown). Side panel 250 alsoincludes partial blinds 255A and 255B for hiding set screw 230 and arecess 253 for receiving screen bar 300 as will be apparent from thediscussion below. If desired, side panel 250 also can include a stop 254for reasons that also will be apparent from the discussion below. Sidepanel 250 and side panel 260 are molded or otherwise readily formed fromresin or plastic such as polypropylene, vinyl, painted ABS(acrylonitrile butadiene styrene) or ASA (acrylonitrile styreneacrylate). Therefore, these side panels can be formed into a variety ofshapes and configurations as is desired.

Although the reinforcing channel 100A of FIG. 1A is discussed hereinwith respect to this embodiment of the present invention, one havingordinary skill in the art would recognize that reinforcing channel 100Bof FIG. 1B, reinforcing channel 100C of FIG. 2C, discussed below, andother configurations are equally applicable, and can be readily receivedby decorative side panel 250 and decorative side panel 260, with onlyslight modifications to the side panels. Therefore, for the sake ofbrevity only, decorative side panels 250 and 260 will be discussed withreference to reinforcing channel 100A. This discussion, however, doesnot limit the invention to the use of reinforcing channel 100A. Rather,other configurations within the concepts of the present invention can beused as desired.

FIG. 2B shows the reinforcing channel 100A of FIG. 2A, for example, withdecorative cover 270 in place. As discussed above, decorative cover 270has been formed by joining decorative side panel 260 to decorative sidepanel 250 using corresponding pins 251A through 251C and receptacles252A and 252B.

FIG. 2B also shows connector caps 272 and 274 that can be used. Ifutilized, these connector caps can be partially inserted into respectiveends 262 and 264 of decorative cover 270 for assisting in securingscreen bar 300 in recess 253 of decorative cover 270. FIG. 2B showsconnector caps 272 and 274 as being tightly secured to legs 110A and120A of reinforcing channel 100A. However, these connectors caps mayjust as well be hollow connectors and not tightly secured to the legs110A and 120A of reinforcing 10A, for the reasons that will be discussedin more detail below. Also, connector caps 272 and 274 can be omittedaltogether, in which case, the screen bar 300 is secured directly todecorative cover 270.

FIG. 2C is a partial cutaway, perspective view showing, as an alternateembodiment of this invention, a reinforcing channel 100C and optionalwheel assembly 200 with a portion of the decorative cover 250 forcovering the wheel assembly 200. The reinforcing channel 100C can bemade of the materials discussed above with respect to reinforcingchannel 100A and reinforcing channel 100B. In this embodiment, thereinforcing channel 100C can be made of more than one piece, or severalpieces, joined together. In one aspect, the reinforcing channel 100C canhave a substantially U-shaped cross section and a bend at approximatelyninety degrees with the ends 180C of the channel 100C being crimped,roll-formed, knurled, welded or otherwise modified to secure extensions181C, to constitute the first and second legs of the reinforcing channel100C. In this embodiment, the extensions are made of standardthree-eighths inch steel reinforcing bar. However, any suitable diameteror any suitable material can be used. Also, the extensions need not becircular in cross section. Rather, any configuration suitable can beused.

In this embodiment, if desired, each screen bar segment 300 can includea retainer 182C to limit or define the foamed region of the screen barsegment 100C. In manufacture, the retainer 182C slides on the extensions(e.g., reinforcing bar) 181C until it hits the modified end (e.g., theroll-formed or crimped section) 180C of the reinforcing channel 100C. Inthis embodiment, it is not necessary for the retainer 182C to provide aone hundred percent seal within the hollow interior portion of thespacer bar 300. Rather, some leakage of the foamed material whichresults in the rigid reinforcing and structural material is acceptable.In this embodiment, by way of example, the reinforcing bar can beapproximately eight inches in length, with approximately seven inches inlength extending on one side of the retainer 182C to be secured by therigid reinforcing and structural material, with approximately one inchbeing crimped or otherwise secured by the end 180C of the reinforcingchannel 100C. Of course, one of skill in the art recognizes that otherlengths can be utilized as desired.

When a retainer 182C is utilized, the foamed chemical is injecteddirectly into the screen bar segment, in a manner discussed in moredetail below, and is substantially retained therein by the retainer182C. If an extension 181C is utilized with the retainer, the portion ofthe extension 181C opposite to the foamed side of the retainer 182C canbe, if necessary, painted or otherwise treated chemically, for example,to protect against weathering, rust, corrosion and the like.

FIG. 3 shows a partially assembled view of one embodiment of the cornerreinforcement of the present invention, in conjunction with thereinforcing channel 100A of FIG. 2B, discussed above, installed in atrack 420 for guiding the screen frame. FIG. 3 shows the joining of afirst segment 305 of screen bar to one end 262 of decorative cover 270.A second segment 315 of screen bar is secured to another end 264 ofdecorative cover 270. If utilized, connector caps 272 and 274 assist insecuring screen bar segment 305 and screen bar segment 315 to decorativecover 270, respectively. If connector caps 272 and 274 are not utilized,then first screen bar segment 305 and second screen bar segment 315 aresecured in respective recesses (for example, 262 shown in FIG. 2B) ofdecorative cover 270. FIG. 3 also shows that first screen bar segment305 can optionally be provided with an insertion opening 306, whilesecond screen bar segment 310 can optionally be provided with aninsertion opening 311. These openings will be discussed in more detailbelow.

If desired, decorative cover 270 can be formed as a sealed unit whendecorative side panels 250 and 260 are joined. In this instance,decorative cover 270 has a closed, hollow interior that is encasedaround wheel 210 and wheel assembly 205. Stop 254 of decorative sidepanel 250 assists in this encasing. In this configuration, decorativecover 270 also can optionally be provided with a corresponding insertionopening 313 for reasons that will be apparent from the discussion below.

FIG. 3 shows that a portion of the first leg 110A of the reinforcingchannel 100A is inserted through a first end of the first screen barsegment 305 into and substantially spaced from a surface of the hollowinterior portion 310 of the first screen bar segment 305 and a portionof the second leg 120A of the reinforcing channel 100A is insertedthrough a first end of the second screen bar segment 315 into andsubstantially spaced from the hollow interior portion 310 of the secondsegment. Of course, one having ordinary skill in the art recognizes thatif the reinforcing channel 100A, for example, is made of separatepieces, rather than being unitary, then one or the other of the legs110A/120A can be installed in the respective screen bar segments. This,of course, is also true for the embodiment shown in FIG. 2C.

FIG. 3 shows that the inserted portions of the reinforcing channel 100Aare sufficiently spaced from the surfaces of the hollow interiorportions of the screen bar segments 305 and 315 for allowing foamedchemical, prior to curing, to pass between the inserted portions and thesurfaces of the hollow interior portions. This arrangement will bediscussed in more detail below.

A probe or equivalent instrument can be inserted in insertion opening306 of first screen bar segment 305 and insertion opening 311 of secondscreen bar segment 315 to inject a foamed material, such aspolyurethane, urea formaldehyde or styrene, for example. Otherequivalent materials could be used. In this manner, the foamed materialcan be injected in the respective insertion openings inside the hollowinterior portion of the first screen bar segment 305 for securing theinserted portion of the first leg 110A of the reinforcing channel 100Atherewithin and/or inside the hollow interior portion 310 of the secondscreen bar segment 315 for securing the inserted portion of the secondleg 120A of the reinforcing channel 100A therewithin. Of course, ifdesired, the foamed material can be injected in one or the other of thescreen bar segments independently, with or without injection into theother screen bar segment. It should be noted that the foamed material,upon curing, not only secures, but also orients the respective legswithin the corresponding segments. In the embodiment of FIG. 2C, forexample, the foamed material can be injected into opening 306 in screenbar segment 300 and be substantially contained by retainer 182C.Retainer 182C can provide up to a one hundred percent seal, or less, ifdesired.

Returning to FIG. 3, rather than using insertion openings 306 and 311,the foamed material could be injected through guide trough 340. This ispreferred, since the use of insertion openings 306 and 311 requires thatdecorative plugs (not shown) be installed to cover the openings. Thistends to be less desirable from an aesthetic standpoint. By injectingthe foamed material into the guide trough, the injection points areunobtrusive. Further, if desired, the foamed material can be injected ininsertion opening 313 or through the guide trough in decorative cover270 as an additional reinforcement to the corner. If connector caps 272and 274 are omitted, or hollow connectors are utilized in conjunctionwith an otherwise sealed decorative cover 270, then the foamed materialcould be injected into the decorative cover 270 directly from the screenbar segments 305 and 315. It is important that the foamed material notinterfere with either the wheel 210 or the wheel assembly 205.Therefore, these elements must be encased or sufficiently protected, asdiscussed above.

The foamed material or equivalent rigid reinforcing and structuralmaterial should have desirable characteristics for use in thisinvention. For example, it should have good adhesion properties so thatit may adhere to metal surfaces, such as the reinforcing channel and thescreen bar segments. Also, it could potentially, but not necessarily,have the ability to adhere to the decorative cover. Also, any materialwhich can be easily manipulated in liquid or semi-liquid form, and whichsolidifies and remains solid at likely operating temperatures, can beused as the rigid reinforcing and structural material, such as, forexample, concrete, cement, plaster, resin, wood-filled resin, hot meltresins, polymers and wood-filled polymers, and clay. However, due totheir ease of production and manipulation, foamed chemicals arepreferred.

In this embodiment, the foamed material is initially a liquid and can beinjected at a pressure anywhere between 50 to 4000 psi depending on thetype of injector used. Although under this pressure, the foamed materialis injected, almost poured into the screen bar segments, since it flowswith a low viscosity. I have found that the liquid stops flowing afterabout 15 seconds, it foams, and then the foam expands until it reachesthe limits of the reinforcing channel or the screen bar. In this regard,the reinforcing channel also could be provided with holes to assist thefoamed material in reaching narrow spaces between the reinforcingchannel and the screen bar. I have found that it is best that the foamedmaterial expand, but not with a tremendous driving force. It may expandat a pressure of approximately 15 psi. Once injected, the foam typicallyexpands until it hits the internal walls of the screen bar. Slightbulging of the screen bar may occur. Therefore, vent holes can beprovided in the screen bar as necessary. The foamed material should becapable of withstanding temperatures between -40° C. and 70° C. Also,the foamed material should not contract upon curing.

I have found that the present invention provides sufficient strength andrigidity without "foaming" the decorative cover. Nevertheless, some maydesire that this portion of the corner reinforcement have a consistent"sound" and "feel" as the remaining corner reinforcement. Therefore, Ihave provided for this aesthetic requirement, as will be discussed inmore detail below.

This invention provides many options, depending upon the configurationof the screen bar segments and the decorative cover 270. In one aspect,if the decorative cover has a "pass-through" design, foamed material canbe injected into one screen bar segment and pass through the decorativecover 270 into the other screen bar segment. Thus, the foamed materialcan travel around the corner of the corner reinforcement to encapsulateboth ends of the reinforcing channel.

In another aspect, if retainer 182C or the connector caps 272 and 274are utilized, the decorative cover 270 is isolated from the foamedmaterial, since the retainer 182C or the connector caps 272 and 274 stopthe penetration of the foamed material into the decorative cover 270. Inturn, the decorative cover 270 can remain hollow or can be injecteddirectly with the foamed material through its guide trough, throughinjection opening 313 or otherwise. It is also then necessary to foamthe screen bar segments individually to encapsulate the legs of thereinforcement individually. This technique, which is preferred, will bediscussed in more detail below.

In a variation, the corner reinforcement itself could provide therequired injection port and passage-ways, to direct the injected foam tothe necessary portions of the corner reinforcement. In this arrangement,the decorative cover 270 would have a modified "pass-through" designwith suitable passage-ways so that the foaming material could beinjected directly into the decorative cover 270 without interfering witheither the wheel 210 or the wheel assembly 205. In this design, noinsertion openings would be required in the sides of the screen bar orthe decorative cover 270. Rather, the foaming material could be injectedfrom the ends of and through the passage-ways of the decorative cover270 along the legs of the reinforcement. The ends of the decorativecover 270 would then be capped unobtrusively and the wheel assembly 200secured. In this design, there would be no visible indication that thecorner reinforcement has been "foamed".

Standard patio screen doors have dimensions on the order of thirty-fourto thirty-six inches in width and seventy-four inches in height. Iprefer that the legs of the corner reinforcement extend into the screenbar with a length of each leg being between 4 to 12 inches. It is morepreferred to use legs 6 inches in length. Legs longer than 12 inches canbe used, but cost then becomes a factor. If, however, the legs are madetoo short, I have found that the cured, foamed material cannot handlethe loading, since the lever force is high, whereas the longerdimensions transmit the loads across a greater distance. Thus, moredistributive loading is achieved with longer leg lengths.

It is known that, for a bar supported at one end (a cantilevered bar), abar 3 feet in length will bend by an amount relative to a bar (made ofidentical material) 2 feet in length by 3³ /2³. Thus, deflection of thecantilevered bar increases significantly with length. I determine anoptimum length of the legs of the corner reinforcement based in part onthis relationship. By increasing the length of the legs, I shorten thelength of any unsupported (unreinforced) profile, by the cubicrelationship noted above.

FIG. 4 shows a cross-sectional view of one embodiment of the cornerreinforcement of the present invention, taken generally along lineIV--IV of FIG. 5. FIG. 4 shows a portion of screen frame assembly 400that includes a reinforcing channel 100A, in this embodiment, which issecured and oriented within rigid reinforcing and structural material450, such as solidified polyurethane foam. Screen frame assembly 400 isguided in track 420 along guide 422. In FIG. 4, the foamed material hasbeen injected into decorative cover 270. FIG. 4 shows that reinforcingchannel 100A is substantially spaced from the surfaces of hollowinterior portion 310 of the screen bar segment 300. In fact, a crosssection of the reinforcing channel 100A is significantly smaller than across section of the hollow interior portion 310 of the screen barsegment 300 for allowing the foamed chemical to pass between thereinforcing channel and the surface of the hollow interior portions.This arrangement, upon curing of the foamed chemical, assists indistributing the loading along the corner reinforcement. Of course, itis acceptable if the reinforcing channel 100A contacts a side wall ofthe screen bar segment 300, since this will not detract from thedistributed loading. Nevertheless, it is important that the insertedportions (e.g., the legs) of the reinforcing channel be sufficientlyspaced from the surfaces of the hollow interior portions of the screenbar segments for allowing passage of the foamed material, prior tocuring.

FIG. 5 shows a screen frame 500 that includes the screen bar cornerreinforcements of the present invention. The screen frame 500 is guidedin tracks 420 and 425. FIG. 5 shows first and second short screen barsegments 510 and 520 and first and second long screen bar segments 530and 540, each of which is formed into a desired profile and each has ahollow interior portion. In this embodiment, each of the four cornershas been reinforced using the corner reinforcements of the presentinvention. Notably, the screen frame 500 utilizes four reinforcingchannels 100A, 100B or 100C, each having a first leg and a second legarranged at approximately 90° to the first leg. A portion of the firstleg of a respective reinforcing channel is inserted through an end ofshort screen bar segment 510/520 into and substantially spaced from asurface of the hollow interior portion of the short segment and aportion of the second leg of a respective reinforcing channel isinserted through an end of each long screen bar segment 530/540 into andsubstantially spaced from a surface of the hollow interior portion ofthe long segment. A rigid reinforcing and structural material 450 (asshown in FIG. 4), formed from a foamed chemical, is inside the hollowinterior portion of each short segment for securing and orientingrespective inserted portions of the first legs of the reinforcingchannels therewithin and the hollow interior portion of each longsegment for securing and orienting respective inserted portions of thesecond legs of the reinforcing channels therewithin.

In making a screen frame 500 including such screen bar cornerreinforcements, first and second short segments of screen bar and firstand second long segments of screen bar are provided, each segment beingformed into a desired profile and each having a hollow interior portion.Four reinforcing channels 100A, 100B or 100C are also provided, eachhaving a first leg and a second leg arranged at approximately 90° to thefirst leg. A portion of the first leg of a respective reinforcingchannel is inserted through an end of a short segment 510/520 of thescreen bar into and substantially spaced from a surface of the hollowinterior portion of the short segment 510/520. A portion of the secondleg of a respective reinforcing channel is inserted through an end of along segment 530/540 of the screen bar into and substantially spacedfrom a surface of the hollow interior portion of the long segment530/540. As discussed above, the inserted portions of the reinforcingchannel should be sufficiently spaced from the surfaces of the hollowinterior portions of the screen bar segments for allowing passage of thefoamed material, prior to curing.

Although it is preferred to reinforce both long and short segments ofeach of the four corners, it is recognized that not all four cornersneed be reinforced, and not all segments of the corners need bereinforced, if this is desired for a particular application. Rather,individual legs or particular corners could be reinforced, as desired,using the concepts of the present invention.

It is preferred to use a corner reinforcement that allows square cutends, as has been shown herein, since less screen bar material isrequired and the corner reinforcement can be designed to allow a closefitting connection between the corner reinforcement and the decorativecover, for example. However, if desired, corner reinforcements allowingmiter (45°) cuts can be used.

After the reinforcing channel is inserted into respective screen barsegments, the members are clamped rigid. The entire assembly (fourcorners) can be clamped together, or the corners can be assembledsingularly and in pairs.

Preferably, a metered amount of premixed liquid polyurethane foam (orother suitable foaming material or equivalent) is injected through aninjection opening into the interior of the corner reinforcement. Iprefer to inject the foaming material into the middle of the short sidesof the screen bar segments, through the guide trough, with the shortsides in a substantially horizontal position. This allows distributionof the foamed material throughout the length of the short sides. I drilla hole in the guide trough, inject the material for approximately onesecond, which hits the bottom of the section and flows to either end,and then insert a temporary plug. Upon curing of the foamed material,the plug is removed and reused. For the long sides of the segments, Ihave found that arranging the segments at approximately ten degrees fromhorizontal is preferred, so that the foamed material is injected atapproximately two thirds of the way up from the bottom of the bar. Thefoamed material will travel up the one third under pressure, and downthe two thirds by pressure and gravity.

I prefer to use foaming material sold under the tradename Vultafoam andsupplied by General Latex Canada Inc. This material becomes rigid afterapproximately ninety seconds. However, any equivalent foaming material,which cures after 5 seconds or up to 5 minutes can be used as desired.This injection can be performed using any of the various techniquesdiscussed above, such as through the screen bar segments, alone, or incombination with the decorative cover, or solely through the decorativecover, either from the side, or end-wise. Sufficient chemical isinjected to result in orientation and securing of the insert, after thepolyurethane (or other foaming material) has fully expanded and cured. Iprefer a density of about 6 to 9 lbs/ft³ after the material becomesrigid. This density should be above 2.5 lbs/ft³ to avoid excessiveshrinkage at low temperatures. To substantially fill each short segment,about 28 to 34 grams of material would be required, depending on thematerial and types of legs used, whereas to substantially fill each longsegment, about 70 grams of material would be required. Of course, it isrecognized that it is not necessary to substantially fill these segmentsin order to achieve the desired results of this invention. Nevertheless,if desired, most clearances can be filled between the inserted portionof the legs of the reinforcing channel and the interior of the screenbar by passing through the spacing between the inserted legs of thecorner reinforcement and the screen bar segments. This thus eliminatesany initial play in the corner reinforcement.

As discussed above, the rigidity of the corner is enhanced by usingreinforcing channels that have legs as long as is practical. Byextending the corner reinforcements deeper into the screen bar segments,the loading at the corner is distributed over a larger area, thusreducing localized stresses, making the corner reinforcement strongerand stiffer. Furthermore, unreinforced spans are reduced or eliminated.

After the foam has cured in the corner assembly, a rigid connection anddistributed loading results, since the cured, foamed material intimatelycontacts all loading areas. As the foam expands in the clearance gaps,the foam exerts a distributed force on these loading areas, in effectpreloading the connection, and increasing stiffness further.

I have found that the screen bar corner reinforcement of this inventionand screen frames made using such corner reinforcements have manyadvantages over conventional arrangements. In particular, the screen barcorner reinforcement of this invention results in a stiffer, stronger"screen bar" for use in screen or other frames. This is true both inbending and torsion. I believe that the shear strength of the screen baris also increased, thus improving mechanical properties overall. Thisimprovement in mechanical properties allows for a reduction in framegauge (thickness) and thus lowers cost. The cost of adding the rigidfoam is less than the savings from the gauge reduction to yield a netcost reduction. Thus, this invention results in cost reduction withsignificantly increased performance.

There are additional benefits. This invention provides increased dentresistance and increased localized buckling resistance of the typicallyroll-foamed frame material. Also, locking of the screen bar joint orseam is less critical, since the expanded rigid foam improves overallintegrity of the profile and increases torsional stiffness and strength.Also, the harder, thinner typically roll-formed material allows fortighter bends on the profile without stressing and cracking any paint onthe surface. This improves aesthetics, and corrosion resistance of theproduct when the screen frame is made of steel. Further, the finalassembly has significantly enhanced consumer appeal. The "feel" of thefinal assembly is denser and less "tinny" than conventional assemblies.This means that the sound of a patio screen door, for example, utilizingthis invention is quieter during rolling as it is opened and closed thanwhen conventional screen doors are used.

The scope of the invention is not limited by the discussion above, butonly by each of the following claims, which should be interpreted asbroadly as possible to encompass all modifications and equivalentstructures without encompassing the prior art or invalidating the claim.

I claim:
 1. A screen bar corner reinforcement for use in strengtheningscreen frames, said reinforcement comprising:at least a first segmentand a second segment of screen bar, each formed into a desired profileand each having a hollow interior portion; a reinforcing channel havinga first leg and a second leg arranged at approximately ninety degrees tothe first leg, with ends of the channel securing first and secondextensions to extend the first and second legs, respectively, at leastone of (i) a portion of the first extension of the reinforcing channelbeing inserted through a first end of the first segment of the screenbar into and substantially spaced from surfaces of the hollow interiorportion of the first segment and (ii) a portion of the second extensionof the reinforcing channel being inserted through a first end of thesecond segment of the screen bar into and substantially spaced fromsurfaces of the hollow interior portion of the second segment; and arigid reinforcing and structural material, formed from a foamedchemical, inside at least one of (i) the hollow interior portion of thefirst segment for securing the inserted portion of the first extensionof the reinforcing channel therewithin and (ii) the hollow interiorportion of the second segment for securing the inserted portion of thesecond extension of the reinforcing channel therewithin.
 2. Areinforcement according to claim 1, in which the inserted portions ofthe reinforcing channel are sufficiently spaced from the surfaces of thehollow interior portions of the screen bar segments for allowing thefoamed chemical, prior to curing, to pass between the inserted portionsand the surfaces of the hollow interior portions.
 3. A reinforcementaccording to claim 1, in which each of the first and second segments ofscreen bar have a recess for securing screen therein and are made of amaterial selected from the group consisting of extruded aluminum,roll-formed aluminum, roll-formed sheet steel, extruded plastic andpultruded, glass-reinforced thermosetting resin.
 4. A reinforcementaccording to claim 1, in which the reinforcing channel is a unitarypiece having a bend of approximately ninety degrees to form the firstand second legs and a cross section of one of substantially U-shape andsubstantially Z-shape.
 5. A reinforcement according to claim 1, in whichthe reinforcing channel is one of plated steel and high strengthplastic.
 6. A reinforcement according to claim 1, in which a crosssection of the reinforcing channel is significantly smaller than a crosssection of the hollow interior portions of the first and second segmentsof screen bar for allowing the foamed chemical, prior to curing, to passbetween the reinforcing channel and surfaces of the hollow interiorportions.
 7. A reinforcement according to claim 1, further comprising awheel mechanism secured to one of the first and second legs of thereinforcing channel, the wheel mechanism including a wheel for beingguided in a track of the screen frame.
 8. A reinforcement according toclaim 7, in which the center line of the wheel mechanism is aligned withthe center line of the one of the first and second legs of thereinforcing channel to which the wheel mechanism is secured.
 9. Areinforcement according to claim 7, further comprising decorative sidepanels for enclosing the wheel mechanism.
 10. A reinforcement accordingto claim 1, in which each of the first and second segments of screen barinclude injection apertures, and the structural material is polyurethanefoaming material having been injected into the first and second segmentsthrough the injection apertures and solidified.
 11. A reinforcementaccording to claim 1, in which the reinforcing channel has asubstantially U-shaped cross section and a bend of approximately ninetydegrees.
 12. A reinforcement according to claim 11, in which thereinforcing channel is one of plated steel and high strength plastic,and the extensions are steel reinforcing bar.
 13. A reinforcementaccording to claim 11, further comprising a retainer within at least oneof the first segment and the second segment of screen bar, forsubstantially containing the rigid reinforcing and structural materialwithin the respective screen bar segment.
 14. A screen frame includingscreen bar corner reinforcements, said frame comprising:first and secondshort segments of screen bar and first and second long segments ofscreen bar, each segment being formed into a desired profile and eachhaving a hollow interior portion; four reinforcing channels, eachreinforcing channel having a first leg and a second leg arranged atapproximately ninety degrees to the first leg, with ends of the channelsecuring first and second extensions to extend the first and secondlegs, respectively, at least one of (i) a portion of the first extensionof a respective reinforcing channel being inserted through an end ofeach short segment of the screen bar into and substantially spaced fromsurfaces of the hollow interior portion of the short segment and (ii) aportion of the second extension of a respective reinforcing channelbeing inserted through an end of each long segment of the screen barinto and substantially spaced from surfaces of the hollow interiorportion of the long segment; and a rigid reinforcing and structuralmaterial, formed from a foamed chemical, inside at least one of (i) thehollow interior portion of each short segment for securing respectiveinserted portions of the first extensions of the reinforcing channelstherewithin and (ii) the hollow interior portion of each long segmentfor securing respective inserted portions of the second extensions ofthe reinforcing channels therewithin.
 15. A frame according to claim 14,in which the inserted portions of the reinforcing channel aresufficiently spaced from the surfaces of the hollow interior portions ofthe screen bar segments for allowing the foamed chemical, prior tocuring, to pass between the inserted portions and the surfaces of thehollow interior portions.
 16. A frame according to claim 14, in whicheach of the segments of screen bar have a recess for securing screentherein and are made of a material selected from the group consisting ofextruded aluminum, roll-formed aluminum, roll-formed sheet steel,extruded plastic and pultruded, glass-reinforced thermosetting resin.17. A frame according to claim 14, in which each reinforcing channel isa unitary piece having a bend at approximately ninety degrees to formthe first and second legs and a cross section of one of substantiallyU-shape and substantially Z-shape.
 18. A frame according to claim 14, inwhich each reinforcing channel is one of plated steel and high strengthplastic.
 19. A frame according to claim 14, in which a cross section ofeach reinforcing channel is significantly smaller than a cross sectionof the hollow interior portions of the segments of screen bar forallowing the foamed chemical, prior to curing, to pass between thereinforcing channel and surfaces of the hollow interior portions.
 20. Aframe according to claim 14, further comprising a wheel mechanismsecured to a respective first leg of each reinforcing channel, the wheelmechanism including a wheel for being guided in a track of the screenframe.
 21. A frame according to claim 20, in which the center line ofthe wheel mechanism is aligned with the center line of the first legs ofthe reinforcing channel to which the wheel mechanism is secured.
 22. Aframe according to claim 20, further comprising decorative side panelsfor enclosing each wheel mechanism.
 23. A frame according to claim 14,in which each of the segments of screen bar includes injectionapertures, and the structural material is polyurethane foaming materialhaving been injected into each of the segments through the injectionapertures and solidified.
 24. A frame according to claim 14, in whichthe reinforcing channel has a substantially U-shaped cross section and abend of approximately ninety degrees.
 25. A frame according to claim 24,in which the reinforcing channel is one of plated steel and highstrength plastic, and the extensions are steel reinforcing bar.
 26. Aframe according to claim 24, further comprising a retainer within atleast one of the first segment and the second segment of screen bar, forsubstantially containing the rigid reinforcing and structural materialwithin the respective screen bar segment.
 27. A method of making ascreen bar corner reinforcement for use in strengthening frames, saidmethod comprising:providing at least a first segment and a secondsegment of screen bar, each being formed into a desired profile and eachhaving a hollow interior portion; providing a reinforcing channel havinga first leg and a second leg arranged at approximately ninety degrees tothe first leg, with ends of the channel securing first and secondextensions to extend the first and second legs, respectively; insertinga portion of the first extension of the reinforcing channel through afirst end of the first segment of the screen bar into and substantiallyspaced from surfaces of the hollow interior portion of the firstsegment; inserting a portion of the second extension of the reinforcingchannel through a first end of the second segment of the screen bar intoand substantially spaced from surfaces of the hollow portion of thesecond segment; and injecting, with a curable reinforcing and structuralmaterial, at least one of (i) the hollow interior portion of the firstsegment for securing the inserted portion of the first extension of thereinforcing channel therewithin and (ii) the hollow interior portion ofthe second segment for securing the inserted portion of the secondextension of the reinforcing channel therewithin.
 28. A method accordingto claim 27, in which the inserted portions of the reinforcing channelare sufficiently spaced from the surfaces of the hollow interiorportions of the screen bar segments for allowing the foamed chemical,prior to curing, to pass between the inserted portions and the surfacesof the hollow interior portions.
 29. A method according to claim 27, inwhich each of the first and second segments of screen bar have a recessfor securing screen therein and are made of a material selected from thegroup consisting of extruded aluminum, roll-formed aluminum, roll-formedsheet steel, extruded plastic and pultruded, glass-reinforcedthermosetting resin.
 30. A method according to claim 27, in which thereinforcing channel is a unitary piece having a bend at approximatelyninety degrees to form the first and second legs and a cross section ofone of substantially U-shape and substantially Z-shape.
 31. A methodaccording to claim 27, in which the reinforcing channel is one of platedsteel and high strength plastic.
 32. A method according to claim 27, inwhich a cross section of the reinforcing channel is significantlysmaller than a cross section of the hollow interior portions of thefirst and second segments of screen bar for allowing the foamedchemical, prior to curing, to pass between the reinforcing channel andsurfaces of the hollow interior portions.
 33. A method according toclaim 27, further comprising securing a wheel mechanism to one of thefirst and second legs of the reinforcing channel, the wheel mechanismincluding a wheel for being guided in a track of the screen frame.
 34. Amethod according to claim 33, further comprising aligning the centerline of the wheel mechanism with the center line of the one of the firstand second legs of the reinforcing channel to which the wheel mechanismis secured.
 35. A method according to claim 33, further comprisingenclosing the wheel mechanism with decorative side panels.
 36. A methodaccording to claim 27, in which the first and second segments of screenbar each include injection apertures, and the structural material ispolyurethane foaming material which is injected in said injecting stepsinto the first and second segments through the injection apertures andcured.
 37. A method according to claim 27, in which the reinforcingchannel has a substantially U-shaped cross section and a bend ofapproximately ninety degrees.
 38. A method according to claim 37, inwhich the reinforcing channel is one of plated steel and high strengthplastic, and the extensions are steel reinforcing bar.
 39. A methodaccording to claim 37, further comprising a retainer within at least oneof the first segment and the second segment of screen bar, forsubstantially containing the rigid reinforcing and structural materialwithin the respective screen bar segment.
 40. A method of making ascreen frame including screen bar corner reinforcements, said methodcomprising:providing first and second short segments of screen bar andfirst and second long segments of screen bar, each segment being formedinto a desired profile and each having a hollow interior portion;providing four reinforcing channels, each channel having a first leg anda second leg arranged at approximately ninety degrees to the first leg,with ends of each channel securing first and second extensions to extendthe first and second legs, respectively; inserting a portion of thefirst extension of a respective reinforcing channel through an end of ashort segment of the screen bar into and substantially spaced fromsurfaces of the hollow interior portion of the short segment; insertinga portion of the second extension of a respective reinforcing channelthrough an end of a long segment of the screen bar into andsubstantially spaced from surfaces of the hollow interior portion of thelong segment; and injecting, with a curable reinforcing and structuralmaterial, at least one of (i) the hollow interior portions of the shortsegments for securing respective inserted portions of the firstextensions of the reinforcing channels therewithin and (ii) the hollowinterior portions of the long segments for securing respective insertedportions of the second extensions of the reinforcing channelstherewithin.
 41. A method according to claim 40, in which the insertedportions of the reinforcing channel are sufficiently spaced from thesurfaces of the hollow interior portions of the screen bar segments forallowing the foamed chemical, prior to curing, to pass between theinserted portions and the surfaces of the hollow interior portions. 42.A method according to claim 40, in which each of the segments of screenbar have a recess for securing screen therein and are made of a materialselected from the group consisting of extruded aluminum, roll-formedaluminum, roll-formed sheet steel, extruded plastic and pultruded,glass-reinforced thermosetting resin.
 43. A method according to claim40, in which each reinforcing channel is a unitary piece having a bendat approximately ninety degrees to form the first and second legs and across section of one of substantially U-shape and substantially Z-shape.44. A method according to claim 40, in which each reinforcing channel isone of plated steel and high strength plastic.
 45. A method according toclaim 40, in which a cross section of each reinforcing channel issignificantly smaller than a cross section of the respective hollowinterior portions of the segments of screen bar for allowing the foamedchemical, prior to curing, to pass between the reinforcing channel andsurfaces of the hollow interior portions.
 46. A method according toclaim 40, further comprising securing a wheel mechanism to a respectivefirst leg of each reinforcing channel, the wheel mechanism including awheel for being guided in a track of the screen frame.
 47. A methodaccording to claim 46, further comprising aligning the center line ofthe wheel mechanism with the center line of a respective leg of thereinforcing channel to which the wheel mechanism is secured.
 48. Amethod according to claim 46, further comprising enclosing the wheelmechanism with decorative side panels.
 49. A method according to claim40, in which each segment of screen bar includes injection apertures,and the structural material is polyurethane foaming material which isinjected in said injecting steps into each of the segments through theinjection apertures and cured.
 50. A method according to claim 40, inwhich the reinforcing channel has a substantially U-shaped cross sectionand a bend of approximately ninety degrees.
 51. A method according toclaim 50, in which the reinforcing channel is one of plated steel andhigh strength plastic, and the extensions are steel reinforcing bar. 52.A method according to claim 50, further comprising a retainer within atleast one of the first segment and the second segment of screen bar, forsubstantially containing the rigid reinforcing and structural materialwithin the respective screen bar segment.